SMS

SMS

send short text and numeric messages to and from digital cell phones,

cell phones and e-mail addresses, as well as cell phones and

public SMS messaging gateways on the Internet

no busy signals

quick service

silent and discreet

SMS alerts

e-mail and SMS are "store and forward" system

utilize a gateway to pass messages from senders to recipients

obvious difference -

length and complexity of the messages

attach files, imbed images, and make use of HTML

IM

virtual real-time text conversations (or chat) with people who are simultaneously connected to the Internet

SMS messages are immediate, but not simultaneous

sms sent and processed by a SMSC